durst



1. AfD-URST.

EMERGENCY SAFETY BRAKE FOR ELEVATORS. APPLICATION FILED 0:21.21. I916-RENEWED Mn. 1. 1919.

1303271 Patented- 11513713, 1919.

2 SHEETS-SHEET.

' I INVENTOR wlmsssss L]&& A D6175 Z ATTORN EY m T N E V m ATTORNEYm/AZ/f 2SHEETS-SHEET Patented May13, 1919.

I LA.DURST. EMERGENCY SAFETY BRAKE FOR ELEVATORS. APPLICATIQN FILED OCT.21. I916- RENEWED MAR. 7, I919.

WITNESSES [Jenn A. BURST, OFPORTLAND, OREGON.

nivrnnenncv SaIfET SC-BRAKE FOR. EL VATORS.

- f ,SiiecificatiblrqflettePatent" Patented May'13, 1919.

Application fi1ed 0ctober27, 191e, senainb. 128,088. Renewed March 7,1919. Serial No. 281,291.

To all whomit may concern: a

Be it known that I, JOHN A. DURST, a citi" zen of the UnitedStates,residing at Portland,- in the county of Multnomah' and StateofOregon, have invented certain new and usefulImprovements in EmergencySafety Brakes for Elevators,of which thefollow ing is a specification;

This invention relatesto an improvement in safety brakes for elevators,and more particularly toan emergencybral're adapted to befitted inconjunctionwith an elevator and so arranged that as the elevatorisoperating under normal conditions this brake mechanism is at all'timesheld 111 an inoperative position but as the hoisting cable ,or chain maybreak or is suddenly released, the brake will become operative to stopthefalling movementof the car'or lift and will maintain the s uneagainstdropping tothe bot tom of the shaft. 1

I An object of my invention is to provide a brake means of the typedescribed which is so arranged that by itself it is not capable ofsettingto a braking position, and to arrange means along the Wall of theshaftin such a manner that as the car may be momentarily released fromits suspension by the cable through slipping of'the same or ispermanently released through breaking of the cable or breaking of someof ,the parts of the cable drum operating mechanismythe brake means willbe gradually setand Will thus bring the car or lift to a gradual thoughpositive stop.

A further objectis to provide means arranged in conjunction with thehoisting cable or chain attaching means for the car or lift that as thecar or lift is suspended through the medium of this cable or chain thebrake means is rendered inoperative, and as raising tension is exertedupon the cable or chain attaching means following the looking of thebrake, the brake may then be man ually released through movement of thebrake setting means. y

WVith the above and other objects in view, my invention consists incertain novel features of construction and combinations of parts whichwill be hereinafter set forth in connection with the drawings and thenmore particularly pointed out in the claims.

In the drawings y Figure 1 is a view taken transversely and horizontallythrough the elevator shaft and looking down upon the top of the elevatorcar.

Fig. 2 is a sectional View of the upper portion of the car having thebrake mecha- Insm mounted thereon and which section is taken on the line2-2 of Fig. 1. l a

Fig. 3 is a view similar to Fig.2 but showing the brakes released.

Fig. 4: is a, fragmentary detail view taken on the line H of Fig. 2. I

Fig. 5 is a detail sectional view of one of the brake shoes, i

Fig. 6 a fragmentary sectional View to show the arrangement of the 1shoe setting means.

Fig. 7 is a fragmentary detail view to show the mounting of the shoe.

The elevator shaft is generally indicated at 1, ai1d the car orjlift bythe reference character 2, it of course being understood thatthe shaftand the lift might be of any approved typeor of some special form to ingmeans and the mounting of the same, it

will be evident that variations might be resortedto without in any,manner affecting the successful operation of the device of my invention.

Bearings 3 and 4: are mounted on the top of the car adjacent to thesides thereof and the toggle links 5 and 6 are connected with thesebearingsand have the rods 7, 8, 9, and lOmounted therein to be capableof endwise sliding movement, it being understood that aplurality ofbearings 3 and toggle links 5 are provided to mount the rods 7 and 8 atone side of thecar in such a relation that theyare alined, While therods 9 and 10 are mounted in a similar mounting at the opposite side ofthe car. These rods 7, 8, 9 and 10 have the brake shoes 11, 12, 13, and14 carried on the ends thereof and secured in any suitablemanner, itbeing preferable that these shoes be made somewhat after the mannershown intFjigsfe and 7 so that -jthey slide 7 through *squared"bearingsin the upper end in similarly formed sockets of the brake shoes, the"parts being thus so mounted that the rods are-held against turningmovement.

means of screws as indicated at 15, or in any other suitable way and 1t1s preferable that the outer faces of each of the brake Sl'lOSS'lJBprovided with a roughened surface as shown -at16.. Y

7 center thereofand is made of sufiicient-size and strength that itwillsupport the entire 1 weight of thecar. A yoke 18 is connectedaroundthisrod or bolt 17and is mounted to r be capableof free. slidingmovement along the length thereof, and a coil sprin "1;9 is

mounted between the upper sideof this-yoke 18 and a cap 2O which is'mountedfion. the

upper end of the rod or bolt 17 and held in attheends thereof andwiththe end of the oke 18 and thus as d-rawin tension is ex- 3 i a ertedupon this yoke 22the pulling strain is exerted-against the spring 19. Acable receiving eye25 isformedasa part of the yoke 22 and the supportingand hoisting cable or Chainffor the elevator can. be connected throughthis eye; By arranging the parts as has beeniabove set fortln when thecable or chain is connected through the eye 25 and is holdingrthe car insuspension, the spring 19. willbe compressed sufficiently that the yoke18 will bear against the lower end of the rim of thecap 20 andconsequently the car will be, positively held in suspensiom but as thetensionof the" cable or chain may be slacked, or maybe released,,thesprings 19 will ex- 'pand to move theyoke 18 downwardly to the positionshown in Figs,2 and 4, the opposite extreme. position being shown inFig. 3.

The yoke 18 has the bearing lugs or ears e tending th efr m .0 ppo eides a d theoperatinglinks 27 and 28 are connected with thesebearingearsto befcapable of swinging movement and at their. outer ends are ferkedas' indicated at 29 and 3O sothat they will connect with the inner endsof the rods]. 8, 9 and .10, it however being under-v stood that therodsa-re arranged to have free sliding movementthrough the forked. endsof the operating links. Brace links 31 and 32 .are connected with theoperatin'g'link 27 7. adjacent to the mounting of the same inconjunction with the yoke 18' and are branched outwardly. to have theirfree ends received around the rods 7 and 8respectively adjacent to'theouter-endsthereof, and s milar brace links 33 and 34; are connected withthe operating link 28 and are extended to have their spread endsreceived around the rods 9 and 10, the-connection of the brace linksbeing such that the several rods are allowed to have the endwise slidingmovement therethrough.

Rack bars 35 and 36 are mounted in any suitable manner to extendvertically along The brake shoesrmaybe secured n place by V the sides ofthe elevator shaft and are so positi'oned that they lie adjacent to theapproximate inner ends of the sets of rods 7 and 8, and 9 and 10respectively. The rods 7 and 8 have oppositely disposedscrew threads onthe approximate inner ends thereof and a gear wheel 37 which has asomewhat elongatedsleeve hub 38 is internally screw threaded, the screwthreads at the opposite ends of the bearing sleeve being right and lefthand to lit the opposed threads of the rods 7 and 8. A gear wheel 39which is similar to the gear wheel 37 and is similarly screw threaded,is mounted on the inner end of the rods 9 and 10, which rods areprovided with right and left hand screw threads. These gear wheels 37and 39 are made of such size that as the drawing tension is exerted uponthe yoke 18 to raise the same, the operating links 27 and 28will swingthe rods which are carried by the toggle links 5 and 6 sufiicientlyinwardly that the wheels will be disengaged from the teeth of the rackbars 35 and 36, but as the drawing tension through the eye 25 isreleased, the spring 19 will force the yoke 18 downwardly andconsequently the operating links27 and 28 together with the brace linksconnected therewith will cause the mrious rods to be moved outwardly ina swinging path around the pivotal connection of tho toggle links 5 and6 with the bearings 3 and 4k in consequence of which the gear wheels 37and 39 will be bronght to mesh with the teeth ofthe racks35 and 3.6. Asthe gear wheels mesh with .the teeth of the rack, downward movement ofthe car will cause these gear wheels to be turned upon the screwthreaded inner ends of the rods 7 and 8, and :9 and 10, and as theserods of the two pairs are oppositely screw threaded, the rods 7 and 8will be extended from their approximate position as will also the rods 9and 10 and the brake shoes 11, 1'2, 13 and 14 will be consequently movedoutwardly. Wear plates 40, 41, 42, and 43. are connected on the sides ofthe elevator shaft 1 and are extended vertically in such mounting thatas the brake shoes are moved outwardly through the actuation of themechanism as hereinbefore described. these brake shoes will have theirroughened faces as indicated at 16 engaged against the wear plates andconsequently a braking action r This locking of the brakes against thethat the brakeshoes will be brought out agalnst the wear plates w th agradual braking pressure and thus the downward movement of the car willbe somewhat gradually slowed down and the car will not be brought toasudden and abrupt stop.

There is of course the possibility that the threads of thevarious rodshaving the brake shoes ethereon mightbe stripped orthreads within thehubs 0f the wheels 37 and 39 might be injured in such a way that theparts would not operate upon turning of the gear wheel, and also thatothercauses might prevent proper operation of the parts, and to guardagainst such occurrences and against the holding of the brake shoes whenthey should be set, it ispreferable that the springs 44 be fitted aroundthe various rods between the ends of the brace links 31, 32, 33, and

34, and the inner ends of the brake shoes 11, 12, 13, and 14 insuchrelation that as the rods may be free through any cause, thesesprings will force the brake shoes out against the wear plates andconsequently; a braking action willybe accomplished which will inclicatethe improper operation of the parts 'or thatportions of the structurearedefective.

wear plates will hold the car not only against downward movement, butalso will prevent upward movement of the same even when the cableorchain is again tightened sufficiently to draw the yoke 1811p against thetension of the spring 19 to a degree that the gear wheels37 and 39 arereleased from the meshing engagement with the teethof the rack bars 35andBG, and therefore it becomes necessary to turn the gear wheels '37and 39 manually or otherwise to again withdraw the rods 7, 8, 9 and 10from the extended position in which they bring the brake shoes to thelocking engagement against the wear plates. A door 45 PIQ. vided in thetop ofthe car and 11118 thus possible for a mechanic or other person togo up onto the top of the car and make adjustment of a new hoistingcable or chain and after the proper pulling tension is exerted againstthe spring, to manually turn the gear wheels 37 and 39 to draw the rodsback to substantially the relation shown in Fig. 1 where the brake shoesare again set in the inoperative position and are released from allbraking action.

From the foregoing it will be seen that I have provided an emergencybrake for elevator cars which is so constructed and arranged that duringproper and normal operation of the elevator the emergency brake meanshas no effect whatever and the car may be operated and controlledwithout recourse to such braking means, but immediately the tension ofthe hoisting cable or chain is slackened as is sometimes occasioned byslipping of the ho1st1ng mechanism or by breaking of the chain orcablefthe brake means will be brought into operation and thexemergencybrakes will be gradually and then positively set. to lock the caragainst falling movement, the operation of the parts being automatic. 1i r While in the foregoing I have shown and described only one specificform of the invention, it will be understood thata number of changes andvariations might beresorted against parts of the elevator shaft when therods are extended, a rack bar mounted on the elevator shaft, a gearwheel having an oppositely threaded internal bore mounted on thethreaded ends of said rods, the mountmg for SillCl rods being soarranged that movement of thesame to throw the gear wheel into and'outof mesh with the teeth of the rack bar is permitted, a connectionfrom the hoist tonormally hold the rods in such position that the gearwheel is out of mesh with the rack bar, and means to move the parts toan opposite position;

upon slacking of the hoist cable.

a 2. An emergency safety brake for elevators of the cable hoist typecomprising rods' mounted adjacent to the sides of the elevator car, rackbars mounted onthe wall of the shaft, sald rods screw threaded at theirinner ends and provided with brake shoes at their outer ends, gearwheels pro vided with internally screw threaded hubs mounted on thescrew threaded ends of said rods, means with which the cablehasconnection to normally hold said gear wheels out of mesh with the teethof the rack bars carried on the sides of the shaft, and means to movesaid gear wheels into engagement with the teeth of the rack bars uponslacking of the cable to thus cause turning of the gear wheels andconsequent extension of the bars to bring the brake shoes thereof intooperative position.

. 3. An emergency safety brake for elevators of the cable hoist typecomprising rods mounted adjacent to the sides of the elevator car, rackbars mounted on the wall of the shaft, said rods screw threaded at theirinner ends and provided with brake shoes at their outer ends, gearwheels provided with internally screw threaded hubs mounted on the screwthreaded ends of said I to bring the brake shoes into operative rela'tion. r

rods, means with which the cable hasconnection to normally'hold saidgear wheels out of mesh with the teeth of the rack bars carried on thesides of the shaft, means to move said gear w-heels into engagement withthe teeth of the rack bars upon slacking of the cable to thus causeturning of the gear wheels and consequent extension of the bars to bringthe brake shoes thereof into operative position, and wear platesarrangedupon the side of the elevator shaft to have the brakeshoes-closethereagainst in the brakf ing' action. r

V An emergency safety brake for elevators of the .cablehoist typecomprising a pair of rods'fo-r each side: of the elevatorcar, means bywhich said rods are mounted to be capable of bodily movement towardandaway from the sidesof the elevatorthereof bored and provided withright and Copies of thisv patent may be obtained for left hand screwthreads mounted on the threaded ends of the rods, rack bars mount ed atthe sides of the elevator shaft, operating links connected with the rodsto cause movement thereof laterally,- a yoke with which the cablehasattachment so arranged that as the cableexerts tension against said yokethe rods and gear wheels will be brought inwardly from the sides of theelevator shaft, and a spring mtroducedto exert bearing tension againstthe-yoke in such a manner thatas the tension of the cable is slackenedthe gear wheels will be moved into mesh with the teeth of the rackbarsand consequently the'rods will be extended from the screw threadedhubs'of the gear wheels 5. An emergency safety brake for elevators ofthe cable hoist type comprising a pair of rods for each side of theelevator car, means by which: said rods are mounted to be capable ofbodily movement toward and away from the sides of the elevator shaft,said rods provided at their outer ends with brake shoes and at theirinner ends provided with right and left hand screw threads;. gear wheelshaving the hubs thereof bored and provided with right and left handscrew threads mounted on the threaded ends of V the rods, rack barsmounted at the sides of the elevator shaft, operating links connectedwith the rods to cause movement thereof laterally, a yoke havingconnection with the operating links and to" which the cable hasattachment so arranged that as the cable exerts tension against saidyoke the rod and gear wheels will be brought inwardly from the sides ofthe elevator shaft, a spring introduced to exert bearing tension againstthe yoke in such a manner that as the tension of the cable is slackenedthe gear wheels will be moved into mesh with the teeth of the rack barsand consequently the rods will be extended from the screw threaded hubsof the gear wheels to bring the brake shoes into operative relation,means by which the movement of the yoke is stopped as the drawing strainof the cable is placed thereon and a positive suspension for the car isaccomplished, and means against which the brake shoes work when extendedto the braking position.

In testimony whereof I aflix my signature in presence of two witnesses.

JOHN A. DURST.

Witnesses:

GEO. F. VVnIsNER, Mrs. Gno. F. WEISNER.

five cents each, by addressing the Commissioner of Patents, Washington,1L0.

